Washington Sunday released images it said prove Russia is shooting across the border into Ukraine to help separatists. The surveillance photos were rejected by Russian officials, who accused the United States of getting its intelligence from social media.

The four black-and-white pictures, released by the Office of the Director of National Intelligence, are said to show artillery in Russia firing across the border and leaving craters around a Ukrainian military unit, the Hill reported. The State Department said the images show "self-propelled artillery only found in Russian military units on the Russian side of the border."

The photos come as Europe considers new sanctions against Russia, increasing pressure that has been building since the downing of Malaysia Airlines Flight MH17 as it flew over separatist-held territory.

The United States began accusing Russia of launching attacks on Ukraine last week. Officials also said separatists had heavy artillery obtained from Russia.

One of the images is dated July 25/26 and is said to show ground scarring from artillery on the Russian side of the border, Time magazine reported.

Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov denied Russia has committed any violations, the Washington Post reported. He advised U.S. intelligence to find more reliable sources of information than social media, ITAR-Tass reported.